Alloy for electrical contacts



Patented D... 15, 1925.

"UNITED STATES PATENT OFFICE.

LELAND A. GARDNER, OF EAST ORANGE. NEW ZI'IIEJQRSEY'. ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY. .A CORPORATION OF NEW YORK.

ALRIOY FOR ELECTRIOAL CONTACTS.

No Drawing.

vented certain Improvements in Alloys for Electrical Contacts, of which the following isa snecification.

This invention relates to electrical contacts. and more particuarly to metallic compositions or alloys adapted to form im-.

proved contacts for electrical instruments.

* An object of the invention is to'prcvide a contact for electrical instruments which i shall require a minimum cost for its manufacture and maintenance, and which shall possess a high degree of efliciency in operation and length of service.

Considerable difiiculty has been experienced in the use of alloys for electrical contacts due to sparking at the contact points.

These alloys have been composed of precious metals having a hardsurface and high melting point. The sparking eventually causes sufficient material to be transferred from one contact to an opposite contact,

thereby closing the gap'between the contacts, or produces erosion or wasting away of the contacts, so that the electrical. instrument becomes inoperative after a comparatively short lengthof service. .Thecontact material to be presently described eliminates these undesirable features and provides a ductile, malleable and substantially homogeneous composition 'of high density consisting of a precious-metal and one or more base metals. By theuse of this ductile and malleable composition, a greater cohesion between the particles thereof is provided so that erosion, wasting away or the flaking ofii' of minute particles caused by the continuous sparking at the contacts, as is the case in other compositions which are of hardand refractory material, is eliminated.

The preferred composition of the contact a material of this invention consists of the following metals and their approximate -proportions: '75% fine gold; 17% nickel; 5% zinc; and 3% cop er. For example, I

have found that the ollowing proportions give. good results: 75% fine gold; 16.7%

Application filed February. 19, 1924. Serial No. 698,900.

nickel; 5.34% zinc; and 2.96% copper.

These metals may be fused and thoroughly hammered cold' and soldered to the contact forming element in a well understood manner. Thus the expensive method of applying the contact material by electro-welding, which is necessary when hard metals are used for this purpose. is eliminated.

While the above materials have been used in substantially the same combination and proportion as outlined above to provide an alloy commercially known as white gold. the use of such material for the purpose of formingscontacts for electrical instruments constitutes a very important advance in providing contacts possessing the characteristics previously recited.

What is claimed is: e

1. As an electric contact material consisting of a major part of fine gold, a lesser part of nickel, a still lesser part of zinc, and a small quantity of copper.

2. A contact point for an electrical switch-- ing device comprising approximately fine gold; 16.7% nickel; 5.34% zinc; and 2.96% copper.

3f Asan electric contact material, a composition of. matter comprising a proximately 75% fine gold;'16.7% nickel; 5.34% zinc;'and 2.96% copper.

4. As an electric contact material consisting of aductile and malleablecomposition of high density comprising approximately 75% fine gold; 16.7% nickel; 5.34% zinc;

and 2.96% copper.

5. As an electric contact material consist-' ing of a ductilev and malleable composition having great cohesion between its particles and adapted to withstand erosion, wasting vaway and fiaking ofi of minutes particles caused by continuous sparking, comprising approximately 7 5% find gold; 16.7% nickel 5.3 1% zinc, and 2.96% copper.

In .testimony whereof, I havev signed my name to this specification this 18th day of February, 1924. L

A 'IJELA D a. GARDNER. 

